Substantial Increase in AKI Incidence Reported

An Irish study documented a sharp rise in acute injury injury incidence from 2005 to 2014.

Incidence rates of acute kidney injury (AKI) have risen dramatically in Ireland, with inpatients at highest risk of experiencing AKI, according to a new study.

In a retrospective cohort study of new entrants into the country's health system, the incidence rates of AKI from 2005 to 2014 increased significantly from 6.1% to 13.2% per 100 patient-years among men and 5.0% to 11.5% per 100 patient-years among women. Stage 1 AKI accounted for the greatest growth in incidence: from 4.4% in 2005 to 10.1% in 2014.

Compared with 2005, patients who entered the health system in 2014 had between 4.5-, 5.2-, and 4.1-fold greater odds of Stage 1, 2, and 3 AKI, respectively, after adjusting for changing demographic and clinical profiles, a team led by Austin G. Stack, MD, of University Hospital Limerick in Limerick, Ireland, reported online ahead of print in Nephrology Dialysis Transplantation.

“Our study has shed new light not only on the overall pattern of AKI incidence over time but also on important trends according to the severity of AKI,” the authors wrote. “Of particular interest is the finding that the greatest absolute increases in AKI incidence were accounted for by increases in AKI Stage 1 from 4.4 to 10.1%, while the growth in Stage 2 (from 0.60 to 1.46%) and Stage 3 (from 0.46 to 0.81%) were less impressive.” The finding suggests that greater attention should be given to these “minor” AKI events and their determinants, according to the investigators.

Incidence rates increased in all clinical settings (the location of patients when renal testing was performed) during the observation period, but was greatest among inpatients than than patients in emergency department, outpatient clinic, and general practice (GP) settings. Compared with GP patients (reference), inpatients, emergency department patients, and outpatients had significant 19-, 6-fold, and 4.4-fold increased odds of a first AKI, in adjusted analyses.

“Our analysis would suggest that targeting of locations where AKI is most likely to occur would be a primary goal,” the investigators noted. “Through early detection strategies including electronic alert systems and adoption of early treatment interventions, it is likely than many AKI events could be prevented and more effectively managed.”

For the study, Dr Stack's team obtained data from Ireland's National Kidney Disease Surveillance System, which is used to monitor trends and outcomes of chronic kidney disease in the Irish health system. The final study cohort included 451,646 patients, of whom 40,786 (9%) experienced a first AKI. The AKI group was significantly older than the no-AKI group (mean 67.5 vs 44.8 years). The investigators defined AKI using Kidney Disease: Improving Global Outcomes (KDIGO) criteria, with Stage 1 defined as a rise in creatinine of 50% to 100% within 7 days or 26.5 µmol/L or greater above baseline within 48 years, Stage 2 as an increase of 100% to 200% above baseline, and Stage 3 as a 200% or greater increase or an increase of 354 µmol/L or greater rise above baseline.